Abstract
Background
Recent pathological studies have suggested that thalamic degeneration may represent a site of non-dopaminergic degeneration in Parkinson's Disease (PD). Our objective was to determine if changes in the thalami could be non-invasively detected in structural MRI images obtained from subjects with Parkinson disease (PD), compared to age-matched controls.
Results
No significant differences in volume were detected in the thalami between eighteen normal subjects and eighteen PD subjects groups. However significant (p &lt; 0.03) shape differences were detected between the Left vs. Right thalami in PD, between the left thalami in PD and controls, and between the right thalami in PD and controls using a recently-developed, spherical harmonic-based representation.
Conclusion
Systematic changes in thalamic shape can be non-invasively assessed in PD in vivo. Shape changes, in addition to volume changes, may represent a new avenue to assess the progress of neurodegenerative processes. Although not directly discernable at the resolution of standard MRI, previous pathological studies would suggest that the shape changes detected in this study represent degeneration in the centre median-parafascicular (CM-Pf) complex, an area known to represent selective non-dopaminergic degeneration in PD.

McKeown, Martin JAffiliation: Pacific Parkinson's Research Center, University of British Columbia, Vancouver, Canada
Brain Research Centre, University of British Columbia, Vancouver, Canada
Department of Medicine (Neurology), University of British Columbia, Vancouver, Canada
Biomedical Signal and Image Computing Lab, Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada

Uthama, AshishAffiliation: Biomedical Signal and Image Computing Lab, Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada

Abugharbieh, RafeefAffiliation: Brain Research Centre, University of British Columbia, Vancouver, Canada
Biomedical Signal and Image Computing Lab, Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada

Palmer, SamanthaAffiliation: Pacific Parkinson's Research Center, University of British Columbia, Vancouver, Canada

Lewis, MechelleAffiliation: Department of Neurology, University of North Carolina at Chapel Hill

Huang, XuemeiAffiliation: Department of Neurology, University of North Carolina at Chapel Hill